• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.632-636
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• 2017

In this study, we design an altitude test facility for hypersonic propulsion engine by constructing a test facility and cold flow test. Cold flow test is performed both with and without test models. The results show that the facility can simulate almost similar altitude condition without any significant change in pressure regardless of test models. We also constructed a database that might be useful for a variable test in the future.

• Advances in aircraft and spacecraft science
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• v.7 no.6
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• pp.553-570
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• 2020

To address the problems caused by the strong coupling of an airbreathing hypersonic vehicle's airframe and propulsion to the integrated control system design, an integrated airframe-propulsion model is established, and the coupling characteristics between the aircraft and engine are analyzed. First, the airframe-propulsion integration model is established based on the typical nonlinear longitudinal dynamical model of an air-breathing hypersonic vehicle and the one-dimensional dual-mode scramjet model. Thrust, moment, angle of attack, altitude, and velocity are used as transfer variables between the aircraft model and the engine model. The one-dimensional scramjet model can accurately reflect the working state of the engine and provide data to support the coupling analysis. Second, owing to the static instability of the aircraft model, the linear quadratic regulator (LQR) controller of the aircraft is designed to ensure attitude stability and height tracking. Finally, the coupling relationship between the aircraft and the engine is revealed through simulation examples. The interaction between vehicle attitude and engine working condition is analyzed, and the influence of vehicle attitude on engine safety is considered. When the engine is in a critical working state, the attitude change of the aircraft will not affect the engine safety without considering coupling, whereas when coupling is considered, the attitude change of the aircraft may cause the engine unstart, which demonstrates the significance of considering coupling characteristics.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.5
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• pp.43-53
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• 2014

Shock tunnels are known to be capable of simulating flow-field environments of supersonic and hypersonic flights. They have been operated successfully world-wide for almost half a century. As a consequence of the strong interest in hypersonic vehicles in Korea, attention has been given on this type of facility and so an intermediate-sized shock tunnel has lately been built at KAIST. In the light of this, this paper presents our tunnel performance and some of the model scramjet test data. The freestream flow used in this work replicates a supersonic combustor environment for a Mach 5.7 flight speed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.321-327
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• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the design method of hypersonic shock tunnel including the conceptual and performance design using theoretical analysis and the quasi 1D Multi-species computational fluid dynamics code.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.72-78
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• 2005

Considerable achievements on scramjet technology have been performed since the end of 1950's when the improvement of performance on ramjet engine was begun. From the viewpoint of rapid and economic efficiency, scramjet propulsion system is presently regarded as the most promising one considered to be applied to the atmospheric hypersonic airplanes and ballistic weapons and even the space launch vehicles. Histories and current trends on scramjet development of USA and Russia are investigated and suggested in this paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.79-85
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• 2005

Considerable achievements on scramjet technology have been performed since the end of 1950's when the improvement of performance on ramjet engine was begun. From the viewpoint of rapid and economic efficiency, scramjet propulsion system is presently regarded as the most promising one considered to be applied to the atmospheric hypersonic airplanes and ballistic weapons and even the space launch vehicles. Histories and current trends on scramjet development of france, Germany, Japan and Australia are investigated and suggested in this paper.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.56-60
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• 2017

In hypersonic aircraft, increase of aerodynamic heat and engine heat leads heat loads in airframe. It could lead structural change of aircraft's component and malfunctioning. Endothermic fuels are liquid hydrocarbon fuels which are able to absorb the heat load by undergoing endothermic reactions. In this study, exo-tetrahydrodicyclopentadiene was selected as a model endothermic fuel and experiments were investigated in endothermic fuel cooling system with zeolite catalyst. Three shapes of catalysts have been manufactured and endothermic characteristics were recovered. Bineded catalyst showed higher heat absorption and conversion than other two zeolite catalysts. In product distribution, binded catalyst showed higher aromatics composition.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.29-41
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• 2021

The PID controller with fin angle and thrust as control input was designed based on the aerodynamic data of scramjet system. Flight simulation following a given trajectory which strike the target point after climb and cruise with constant dynamic pressure was conducted. After that, the required thrust for the climb and cruise was calculated and the required fuel flow rate for the hydrogen fuel dual mode scramjet combustor was analyzed. The combustor analysis of this study which conducted on integrated model of independently developed inlet, combustor, nozzles and external aerodynamic models, laying the foundation for the integrated design of the air breathing hypersonic system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.492-498
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• 2008

In this paper are described recent studies about variable nozzles, that are a rectangular type nozzle and an axisymmetric type nozzle, of the precooled turbojet engine(S-engine) which are developed for the demonstration of the key technologies for the propulsion system of the hypersonic airplane and the first stage propulsion of the TSTO space plane. For the rectangular nozzle, three types of C-shaped carbon/carbon composite cowls which includes subscale model of the precooled turbojet engine are fabricated and the fine attachment to the ramp is confirmed. For the firing of the S-engine, stainless steel cowl with concrete heat insulator are fabricated and tested for 20 sec. Axisymmetric variable plug nozzle which is made of C/C material is fabricated and pressurized by the cold flow test. The axisymmetric plug nozzle can be operative up to 0.57 MPa of nozzle inlet pressure.

• Transactions on Control, Automation and Systems Engineering
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• v.1 no.1
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• pp.75-86
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• 1999

An air-data estimator for generic air-breathing hypersonic vehicles (AHSVs) is developed and demonstrated with an example vehicle configuration. The AHSV air-data estimation strategy emphasized improvement of the angle of attack estimate accuracy to a degree necessitated by the stringent operational requirements of the air-breathing propulsion. the resulting estimation problem involves highly nonlinear diffusion process (propagation); consequently, significant distortion of a posteriori conditional density is suspected. A simulation based statistical analysis tool is developed to characterize the nonlinear diffusion process. The statistical analysis results indicate that the diffusion process preserves the symmetry and unimodality of initial probability density shape state variables, and provide the basis for applicability of an Extended Kalman Filter (EKF). An EKF is designed for the AHSV air-data system and the air data estimation capabilities are demonstrated.